v1-0007-Transaction-chaining.patch

From 65bfb7be0aee872eb0405a77ec23ee2483745b37 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Fri, 16 Feb 2018 21:37:55 -0500
Subject: [PATCH v1 7/8] Transaction chaining

Add command variants COMMIT AND CHAIN and ROLLBACK AND CHAIN, which
start new transactions with the same transaction characteristics as the
just finished one, per SQL standard.
---
 doc/src/sgml/ref/abort.sgml                |  14 ++-
 doc/src/sgml/ref/commit.sgml               |  14 ++-
 doc/src/sgml/ref/end.sgml                  |  14 ++-
 doc/src/sgml/ref/rollback.sgml             |  14 ++-
 src/backend/access/transam/xact.c          |  74 ++++++++++++++-
 src/backend/nodes/copyfuncs.c              |   1 +
 src/backend/nodes/equalfuncs.c             |   1 +
 src/backend/parser/gram.y                  |  19 +++-
 src/backend/tcop/utility.c                 |   4 +-
 src/include/access/xact.h                  |   4 +-
 src/include/nodes/parsenodes.h             |   1 +
 src/test/regress/expected/transactions.out | 139 +++++++++++++++++++++++++++++
 src/test/regress/sql/transactions.sql      |  49 ++++++++++
 13 files changed, 333 insertions(+), 15 deletions(-)

diff --git a/doc/src/sgml/ref/abort.sgml b/doc/src/sgml/ref/abort.sgml
index 21799d2a83..0372913365 100644
--- a/doc/src/sgml/ref/abort.sgml
+++ b/doc/src/sgml/ref/abort.sgml
@@ -21,7 +21,7 @@
 
  <refsynopsisdiv>
 <synopsis>
-ABORT [ WORK | TRANSACTION ]
+ABORT [ WORK | TRANSACTION ] [ AND [ NO ] CHAIN ]
 </synopsis>
  </refsynopsisdiv>
 
@@ -51,6 +51,18 @@ <title>Parameters</title>
      </para>
     </listitem>
    </varlistentry>
+
+   <varlistentry>
+    <term><literal>AND CHAIN</literal></term>
+    <listitem>
+     <para>
+      If <literal>AND CHAIN</literal> is specified, a new transaction is
+      immediately started with the same transaction characteristics (see <xref
+      linkend="sql-set-transaction"/>) as the just finished one.  Otherwise,
+      no new transaction is started.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </refsect1>
 
diff --git a/doc/src/sgml/ref/commit.sgml b/doc/src/sgml/ref/commit.sgml
index b2e8d5d180..37c706a66f 100644
--- a/doc/src/sgml/ref/commit.sgml
+++ b/doc/src/sgml/ref/commit.sgml
@@ -21,7 +21,7 @@
 
  <refsynopsisdiv>
 <synopsis>
-COMMIT [ WORK | TRANSACTION ]
+COMMIT [ WORK | TRANSACTION ] [ AND [ NO ] CHAIN ]
 </synopsis>
  </refsynopsisdiv>
 
@@ -48,6 +48,18 @@ <title>Parameters</title>
      </para>
     </listitem>
    </varlistentry>
+
+   <varlistentry>
+    <term><literal>AND CHAIN</literal></term>
+    <listitem>
+     <para>
+      If <literal>AND CHAIN</literal> is specified, a new transaction is
+      immediately started with the same transaction characteristics (see <xref
+      linkend="sql-set-transaction"/>) as the just finished one.  Otherwise,
+      no new transaction is started.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </refsect1>
 
diff --git a/doc/src/sgml/ref/end.sgml b/doc/src/sgml/ref/end.sgml
index 7523315f34..8b8f4f0dbb 100644
--- a/doc/src/sgml/ref/end.sgml
+++ b/doc/src/sgml/ref/end.sgml
@@ -21,7 +21,7 @@
 
  <refsynopsisdiv>
 <synopsis>
-END [ WORK | TRANSACTION ]
+END [ WORK | TRANSACTION ] [ AND [ NO ] CHAIN ]
 </synopsis>
  </refsynopsisdiv>
 
@@ -50,6 +50,18 @@ <title>Parameters</title>
      </para>
     </listitem>
    </varlistentry>
+
+   <varlistentry>
+    <term><literal>AND CHAIN</literal></term>
+    <listitem>
+     <para>
+      If <literal>AND CHAIN</literal> is specified, a new transaction is
+      immediately started with the same transaction characteristics (see <xref
+      linkend="sql-set-transaction"/>) as the just finished one.  Otherwise,
+      no new transaction is started.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </refsect1>
 
diff --git a/doc/src/sgml/ref/rollback.sgml b/doc/src/sgml/ref/rollback.sgml
index 3cafb848a9..3019273a47 100644
--- a/doc/src/sgml/ref/rollback.sgml
+++ b/doc/src/sgml/ref/rollback.sgml
@@ -21,7 +21,7 @@
 
  <refsynopsisdiv>
 <synopsis>
-ROLLBACK [ WORK | TRANSACTION ]
+ROLLBACK [ WORK | TRANSACTION ] [ AND [ NO ] CHAIN ]
 </synopsis>
  </refsynopsisdiv>
 
@@ -47,6 +47,18 @@ <title>Parameters</title>
      </para>
     </listitem>
    </varlistentry>
+
+   <varlistentry>
+    <term><literal>AND CHAIN</literal></term>
+    <listitem>
+     <para>
+      If <literal>AND CHAIN</literal> is specified, a new transaction is
+      immediately started with the same transaction characteristics (see <xref
+      linkend="sql-set-transaction"/>) as the just finished one.  Otherwise,
+      no new transaction is started.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </refsect1>
 
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 15edc93d91..3e468f4d38 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -189,6 +189,7 @@ typedef struct TransactionStateData
 	bool		startedInRecovery;	/* did we start in recovery? */
 	bool		didLogXid;		/* has xid been included in WAL record? */
 	int			parallelModeLevel;	/* Enter/ExitParallelMode counter */
+	bool		chain;			/* start a new block after this one */
 	struct TransactionStateData *parent;	/* back link to parent */
 } TransactionStateData;
 
@@ -220,6 +221,7 @@ static TransactionStateData TopTransactionStateData = {
 	false,						/* startedInRecovery */
 	false,						/* didLogXid */
 	0,							/* parallelModeLevel */
+	false,						/* chain */
 	NULL						/* link to parent state block */
 };
 
@@ -2738,6 +2740,36 @@ StartTransactionCommand(void)
 	MemoryContextSwitchTo(CurTransactionContext);
 }
 
+
+/*
+ * Simple system for saving and restoring transaction characteristics
+ * (isolation level, read only, deferrable).  We need this for transaction
+ * chaining, so that we can set the characteristics of the new transaction to
+ * be the same as the previous one.  (We need something like this because the
+ * GUC system resets the characteristics at transaction end, so for example
+ * just skipping the reset in StartTransaction() won't work.)
+ */
+static int	save_XactIsoLevel;
+static bool	save_XactReadOnly;
+static bool	save_XactDeferrable;
+
+static void
+SaveTransactionCharacteristics(void)
+{
+	save_XactIsoLevel = XactIsoLevel;
+	save_XactReadOnly = XactReadOnly;
+	save_XactDeferrable = XactDeferrable;
+}
+
+static void
+RestoreTransactionCharacteristics(void)
+{
+	XactIsoLevel = save_XactIsoLevel;
+	XactReadOnly = save_XactReadOnly;
+	XactDeferrable = save_XactDeferrable;
+}
+
+
 /*
  *	CommitTransactionCommand
  */
@@ -2746,6 +2778,9 @@ CommitTransactionCommand(void)
 {
 	TransactionState s = CurrentTransactionState;
 
+	if (s->chain)
+		SaveTransactionCharacteristics();
+
 	switch (s->blockState)
 	{
 			/*
@@ -2797,6 +2832,13 @@ CommitTransactionCommand(void)
 		case TBLOCK_END:
 			CommitTransaction();
 			s->blockState = TBLOCK_DEFAULT;
+			if (s->chain)
+			{
+				StartTransaction();
+				s->blockState = TBLOCK_INPROGRESS;
+				s->chain = false;
+				RestoreTransactionCharacteristics();
+			}
 			break;
 
 			/*
@@ -2816,6 +2858,13 @@ CommitTransactionCommand(void)
 		case TBLOCK_ABORT_END:
 			CleanupTransaction();
 			s->blockState = TBLOCK_DEFAULT;
+			if (s->chain)
+			{
+				StartTransaction();
+				s->blockState = TBLOCK_INPROGRESS;
+				s->chain = false;
+				RestoreTransactionCharacteristics();
+			}
 			break;
 
 			/*
@@ -2827,6 +2876,13 @@ CommitTransactionCommand(void)
 			AbortTransaction();
 			CleanupTransaction();
 			s->blockState = TBLOCK_DEFAULT;
+			if (s->chain)
+			{
+				StartTransaction();
+				s->blockState = TBLOCK_INPROGRESS;
+				s->chain = false;
+				RestoreTransactionCharacteristics();
+			}
 			break;
 
 			/*
@@ -3481,7 +3537,7 @@ PrepareTransactionBlock(const char *gid)
 	bool		result;
 
 	/* Set up to commit the current transaction */
-	result = EndTransactionBlock();
+	result = EndTransactionBlock(false);
 
 	/* If successful, change outer tblock state to PREPARE */
 	if (result)
@@ -3527,7 +3583,7 @@ PrepareTransactionBlock(const char *gid)
  * resource owner, etc while executing inside a Portal.
  */
 bool
-EndTransactionBlock(void)
+EndTransactionBlock(bool chain)
 {
 	TransactionState s = CurrentTransactionState;
 	bool		result = false;
@@ -3653,6 +3709,13 @@ EndTransactionBlock(void)
 			break;
 	}
 
+	Assert(s->blockState == TBLOCK_STARTED ||
+		   s->blockState == TBLOCK_END ||
+		   s->blockState == TBLOCK_ABORT_END ||
+		   s->blockState == TBLOCK_ABORT_PENDING);
+
+	s->chain = chain;
+
 	return result;
 }
 
@@ -3663,7 +3726,7 @@ EndTransactionBlock(void)
  * As above, we don't actually do anything here except change blockState.
  */
 void
-UserAbortTransactionBlock(void)
+UserAbortTransactionBlock(bool chain)
 {
 	TransactionState s = CurrentTransactionState;
 
@@ -3761,6 +3824,11 @@ UserAbortTransactionBlock(void)
 				 BlockStateAsString(s->blockState));
 			break;
 	}
+
+	Assert(s->blockState == TBLOCK_ABORT_END ||
+		   s->blockState == TBLOCK_ABORT_PENDING);
+
+	s->chain = chain;
 }
 
 /*
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index b013539ee9..7e0a0a90d5 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -3603,6 +3603,7 @@ _copyTransactionStmt(const TransactionStmt *from)
 	COPY_NODE_FIELD(options);
 	COPY_STRING_FIELD(savepoint_name);
 	COPY_STRING_FIELD(gid);
+	COPY_SCALAR_FIELD(chain);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index ba5ebdf408..8e22a97818 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1514,6 +1514,7 @@ _equalTransactionStmt(const TransactionStmt *a, const TransactionStmt *b)
 	COMPARE_NODE_FIELD(options);
 	COMPARE_STRING_FIELD(savepoint_name);
 	COMPARE_STRING_FIELD(gid);
+	COMPARE_SCALAR_FIELD(chain);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ecb2494226..a5e75c9cbf 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -309,6 +309,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 %type <boolean>	opt_or_replace
 				opt_grant_grant_option opt_grant_admin_option
 				opt_nowait opt_if_exists opt_with_data
+				opt_transaction_chain
 %type <ival>	opt_nowait_or_skip
 
 %type <list>	OptRoleList AlterOptRoleList
@@ -9826,11 +9827,12 @@ UnlistenStmt:
  *****************************************************************************/
 
 TransactionStmt:
-			ABORT_P opt_transaction
+			ABORT_P opt_transaction opt_transaction_chain
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_ROLLBACK;
 					n->options = NIL;
+					n->chain = $3;
 					$$ = (Node *)n;
 				}
 			| BEGIN_P opt_transaction transaction_mode_list_or_empty
@@ -9847,25 +9849,28 @@ TransactionStmt:
 					n->options = $3;
 					$$ = (Node *)n;
 				}
-			| COMMIT opt_transaction
+			| COMMIT opt_transaction opt_transaction_chain
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_COMMIT;
 					n->options = NIL;
+					n->chain = $3;
 					$$ = (Node *)n;
 				}
-			| END_P opt_transaction
+			| END_P opt_transaction opt_transaction_chain
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_COMMIT;
 					n->options = NIL;
+					n->chain = $3;
 					$$ = (Node *)n;
 				}
-			| ROLLBACK opt_transaction
+			| ROLLBACK opt_transaction opt_transaction_chain
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_ROLLBACK;
 					n->options = NIL;
+					n->chain = $3;
 					$$ = (Node *)n;
 				}
 			| SAVEPOINT ColId
@@ -9965,6 +9970,12 @@ transaction_mode_list_or_empty:
 					{ $$ = NIL; }
 		;
 
+opt_transaction_chain:
+			AND CHAIN		{ $$ = true; }
+			| AND NO CHAIN	{ $$ = false; }
+			| /* EMPTY */	{ $$ = false; }
+		;
+
 
 /*****************************************************************************
  *
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 2d29778787..35d21c23d5 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -434,7 +434,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 						break;
 
 					case TRANS_STMT_COMMIT:
-						if (!EndTransactionBlock())
+						if (!EndTransactionBlock(stmt->chain))
 						{
 							/* report unsuccessful commit in completionTag */
 							if (completionTag)
@@ -465,7 +465,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 						break;
 
 					case TRANS_STMT_ROLLBACK:
-						UserAbortTransactionBlock();
+						UserAbortTransactionBlock(stmt->chain);
 						break;
 
 					case TRANS_STMT_SAVEPOINT:
diff --git a/src/include/access/xact.h b/src/include/access/xact.h
index 87ae2cd4df..12db48c6b8 100644
--- a/src/include/access/xact.h
+++ b/src/include/access/xact.h
@@ -349,9 +349,9 @@ extern void StartTransactionCommand(void);
 extern void CommitTransactionCommand(void);
 extern void AbortCurrentTransaction(void);
 extern void BeginTransactionBlock(void);
-extern bool EndTransactionBlock(void);
+extern bool EndTransactionBlock(bool chain);
 extern bool PrepareTransactionBlock(const char *gid);
-extern void UserAbortTransactionBlock(void);
+extern void UserAbortTransactionBlock(bool chain);
 extern void BeginImplicitTransactionBlock(void);
 extern void EndImplicitTransactionBlock(void);
 extern void ReleaseSavepoint(const char *name);
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index e3a63e9db4..391b1033d6 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2967,6 +2967,7 @@ typedef struct TransactionStmt
 	List	   *options;		/* for BEGIN/START commands */
 	char	   *savepoint_name;	/* for savepoint commands */
 	char	   *gid;			/* for two-phase-commit related commands */
+	bool		chain;			/* AND CHAIN option */
 } TransactionStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/transactions.out b/src/test/regress/expected/transactions.out
index fa7fccc63b..4b4272b4e9 100644
--- a/src/test/regress/expected/transactions.out
+++ b/src/test/regress/expected/transactions.out
@@ -659,6 +659,145 @@ ERROR:  portal "ctt" cannot be run
 COMMIT;
 DROP FUNCTION create_temp_tab();
 DROP FUNCTION invert(x float8);
+-- Tests for AND CHAIN
+CREATE TABLE abc (a int);
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, DEFERRABLE;
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES (1);
+INSERT INTO abc VALUES (2);
+COMMIT AND CHAIN;  -- TBLOCK_END
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES ('error');
+ERROR:  invalid input syntax for integer: "error"
+LINE 1: INSERT INTO abc VALUES ('error');
+                                ^
+INSERT INTO abc VALUES (3);  -- check it's really aborted
+ERROR:  current transaction is aborted, commands ignored until end of transaction block
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES (3);
+COMMIT;
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, DEFERRABLE;
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+SAVEPOINT x;
+INSERT INTO abc VALUES ('error');
+ERROR:  invalid input syntax for integer: "error"
+LINE 1: INSERT INTO abc VALUES ('error');
+                                ^
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES (4);
+COMMIT;
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, DEFERRABLE;
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES (5);
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+INSERT INTO abc VALUES ('error');
+ERROR:  invalid input syntax for integer: "error"
+LINE 1: INSERT INTO abc VALUES ('error');
+                                ^
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+ transaction_isolation 
+-----------------------
+ repeatable read
+(1 row)
+
+SHOW transaction_deferrable;
+ transaction_deferrable 
+------------------------
+ on
+(1 row)
+
+ROLLBACK;
+SELECT * FROM abc ORDER BY 1;
+ a 
+---
+ 1
+ 2
+ 3
+ 4
+(4 rows)
+
+DROP TABLE abc;
 -- Test assorted behaviors around the implicit transaction block created
 -- when multiple SQL commands are sent in a single Query message.  These
 -- tests rely on the fact that psql will not break SQL commands apart at a
diff --git a/src/test/regress/sql/transactions.sql b/src/test/regress/sql/transactions.sql
index 82661ab610..4d56fab464 100644
--- a/src/test/regress/sql/transactions.sql
+++ b/src/test/regress/sql/transactions.sql
@@ -419,6 +419,55 @@ CREATE FUNCTION create_temp_tab() RETURNS text
 DROP FUNCTION invert(x float8);
 
 
+-- Tests for AND CHAIN
+
+CREATE TABLE abc (a int);
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, DEFERRABLE;
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (1);
+INSERT INTO abc VALUES (2);
+COMMIT AND CHAIN;  -- TBLOCK_END
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES ('error');
+INSERT INTO abc VALUES (3);  -- check it's really aborted
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (3);
+COMMIT;
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, DEFERRABLE;
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+SAVEPOINT x;
+INSERT INTO abc VALUES ('error');
+COMMIT AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (4);
+COMMIT;
+
+START TRANSACTION ISOLATION LEVEL REPEATABLE READ, DEFERRABLE;
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES (5);
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_PENDING
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+INSERT INTO abc VALUES ('error');
+ROLLBACK AND CHAIN;  -- TBLOCK_ABORT_END
+SHOW transaction_isolation;
+SHOW transaction_deferrable;
+ROLLBACK;
+
+SELECT * FROM abc ORDER BY 1;
+
+DROP TABLE abc;
+
+
 -- Test assorted behaviors around the implicit transaction block created
 -- when multiple SQL commands are sent in a single Query message.  These
 -- tests rely on the fact that psql will not break SQL commands apart at a
-- 
2.16.2